Studies were carried out in the years 2008-2010 in Lake Starzyc, zachodniopomorskie voivodship. The aim was to determine differences in the concentrations of selected water quality parameters between particular months of the vegetation seasons 2008-2010. Monthly mean concentrations of dissolved oxygen between April and October were by 1.91 g O2m-3 higher in surface than in near-bottom water layer. Differences in the concentration of dissolved oxygen were also noted between particular months. Recorded concentrations fell within the range required for lake waters of the first and second water quality. Concentrations of mineral nitrogen in the years 2008-2010 corresponded to those of the third class of water quality and phosphorus concentrations exceeded this standard. Concentrations of ammonium ions did not exceed the values permitted for the second water quality class.
The round goby (Neogobius melanostomus Pallas, 1811) is one of the most invasive fish species in the world, including Poland. 300 fish of this species were collected in the waters of Szczecin lagoon between 2010 and 2014 and examination of the size, sex and age structures of the population and of the condition of the fish was performed. Total length and standard length of all the collected fish amounted to 149.2 mm (±42.21) and 128.1 mm (±38.65), respectively. The age structure of the fish consisted of nine generations, with clear prevalence of the fish aged 3+ and 4+. Mean values of condition factors for the whole fish sample amounted to 0.20 (±0.02). However, no statistically significant differences in particular years were observed (ANOVA, p > 0.05), but the condition of the fish between 2010 and 2011 was slightly higher than between 2013 and 2014. The obtained results indicate that the Szczecin Lagoon environment provides this species with favourable living conditions and it can be stipulated that the quantity of individuals of this fish species will increase.
Due to poor ecological status of Lake Starzyc, lake restoration measures were undertaken in 2003 to improve aerobic conditions of near-bottom waters and to decrease phosphorus concentrations. To do this, a wind-driven pulverising aerator was installed in the lake. The aim of this study was to analyse variability of oxygen and nitrogen concentrations in lake water near the aerator in the third year of its operation and later on in the three-year-long period of the years 2008–2010. It was found that concentrations of ammonium-nitrogen, nitrate-nitrogen and dissolved oxygen near the aerator did not differ from those in sites 4 and 5, which evidenced similar abiotic conditions in analysed waters. Higher concentrations of dissolved oxygen and lower concentrations of nitrate-nitrogen were found in the years 2008–2010 than in 2005.
Międzyodrze is an area in Lower Odra Valley, from the fork of the riverbed to Szczecin, with the islands between the Odra River and Lake Dąbie. In the past, it has served primarily as a waterway route and now serves a variety of economic and nature-related functions. This paper presents the historical and present role of Międzyodrze, taking into account the specific natural values of the Lower Odra Valley, hydrography, hydrology and soil conditions. In the area of Międzyodrze, there are basically three types of organic matter and the nature’s point of view, the area is rich in flora and fauna. The current stimulation to activity of Międzyodrze is to take account of the needs of the natural environment, tourism and recreation, while improving the hydrological and retention potential of the area. Exceptional natural values, complicated hydraulic system of canals, the complexity of hydrological phenomena and the specificity of soils make the selection of activities aimed at achieving the objectives of area revitalization requires comprehensive environmental and hydrological analyses as well as economic analyses. The paper outlined the range of difficulties encountered by this assessment.
Monitoring studies of ichthyofauna, in particular non-indigenous species, are an important element of research on aquatic ecosystems. This information is essential for modelling population growth and predicting rates of expansion, quantifying ecological impacts and assessing the efficacy of removal and control strategies. Actually, the most compelling fish invasion in Polish freshwaters is arguably the accidental introduction of the topmouth gudgeon (Pseudorasbora parva). Age and lengths structure, condition factor and growth rate of the invasive populations of the topmouth gudgeon from small Polish rivers was examined. The samples were collected from the rivers: Molnica (n = 41), Myśla (n = 21) and Wardynka (n = 101) soon after the invasion was recorded (2017). Estimated ages of topmouth gudgeon ranged from 1+ to 3+ for the Myśla River, from 1+ do 4+ for the Molnica River, and from 1+ to 5+ for the Wardynka River. The fish from the Molnica River was characterised by the lowest total and standard length (TL, SL), weight, and highest condition. The results of back-calculations and the parameters of von Bertalanffy’s growth equation revealed distinct disproportions in the standard length (mm) in individual age groups (Molnica River: Lt = 54.94 [1 – e−0.68885 (1 − 0.003404)], Myśla River: Lt = 55.39 [1 – e−0.74921 (1 – 0.030962)], Wardynka River: Lt = 66.33 [1 – e−0.69348 (1 – 0.369505)]). The introduction of the topmouth gudgeon occurred in the upper and medium sectors of small rivers, but in subsequent years the species migrated to new sites further downstream and this may have affected the native ichthyofauna.
Fish farming and especially rearing and breeding of rainbow trout and carp is one of potential sources of surface water pollution. The study was aimed at assessing the effect of a rainbow trout farm on water quality in the Gowienica River in winter. Temperature, pH, electrolytic conductivity, total suspended solids, dissolved oxygen, BOD5, CODCr, alkalinity, water hardness, calcium, magnesium, ammonium-nitrogen, nitrate-nitrogen (III and V) and total phosphorus were determined according to Polish Norms and APHA  in water samples collected in winter up- and downstream the study object. The increment of pollutant concentrations in rainbow trout farm effluents was referred to the requirements in Rozporządzenie MŚ . Performed studies and literature review show that effluents from the assessed fish farm did not worsen water quality of the river. Increased concentrations of total suspended solids and CODCr in effluents were noted only in March. According to data from the report on environmental status in zachodniopomorskie province in the years 2008-2011, poor water quality of the Gowienica River is recorded already upstream the rainbow trout farm. Pollution of this stretch of the river may originate from uncontrolled waste water management and from nutrient runoff from fields.